Well cementing

ABSTRACT

Wells and like borings into the earth&#39;s surface, especially those for the production of petroleum and gas, are very well and efficaciously cemented with cement compositions or pastes containing, as their effective gel control and cement set retardation agent, an additive that is a resulfonated, alkaline oxidized, hydrolyzed, partially desulfonated lignosulfonate product.

This is a division of application Ser. No. 671,159, filed Mar. 29, 1976,now U.S. Pat. No. 4,065,318.

GENERAL BACKGROUND OF THE INVENTION

The increased number of deep wells being drilled and the encounterments,during drilling, of abnormally high temperature gradients has led to thedevelopment of cement retarders to be used to help extend thepumpability of manufactured cements currently available. It is extremelydesirable in such connection to have longer thickening times in thecementing compositions employed when they are used under hightemperature conditions. These demands, oftentimes, cannot be met withpresently available (including commercial) retarded cements (such as APIClasses D and E).

At the present time, very few cementing compositions are used to cementwells below 12,000 feet where static temperatures are in excess of 260°F., unless additional retarder is utilized. Observation of cementingcompositions currently used in wells 10,000 feet and deeper indicatesthat a large number of the compositions employed contain additives tomodify the properties of the basic cement. These additives, in additionto retarders, can frequently be light-weight clay and equivalent mineralmaterials (such as bentonite, Diacel D, etc.) silica flour, heavy-weightmaterials (such as Hi-Dense No. 2, barite, etc.) or any of the manyother materials and component additives available for altering theproperties of the cement composition used.

The selection of a retarder that will be compatible with themanufactured retarded cements, which in themselves usually contain aretarder, sometimes becomes a difficult task. Compounds such as lignins(salts of lignosulfonic acid), gums, starches, various weak (oftentimesorganic) acids, and cellulose derivatives have been used in themanufacture of commercial retarded cements. One of the first retardersdeveloped in the trade was a blend of borax, boric acid and gum arabic.Due to blending problems, this retarder was exceedingly difficult tohandle at bulk cement plants. Nonetheless, much actual use has been hadof such retarders for commercial retarded cements prior to the time thatameliorated retarders were developed.

The primary factor and influence that governs the use of additionalretarder is the temperature of the well. As the temperature increases,the chemical reaction between the cement and water is accelerated. This,in turn, reduces the thickening time or pumpability of the cementcomposition or paste. The use of additives with high water ratios alsonecessitates the use of additional retarder to obtain the desiredthickening time. This can be due to one or both of the followingfundamental factors, namely: (1) high surface materials, which generallyhave high water requirements, which adsorb part of the retarder leavingless to affect the retardation of the cement; and (2) additional waterwhich further dilutes the concentration of retarder and thereby reducesits retarding potential.

Most currently available retarders can be used with the basic cementingcompositions containing API Class A, D, or E cements, Pozmix-Cement andPozmix 140 blended with various additives. Appropriate test dataavailable in the art coupled with developed laboratory observations canindicate the performance of cementing compositions and the like with andwithout retarder when used to depths of 12,000 feet or where statictemperatures are in the range of 260° to 275° F. Where bottom holeconditions exceed these values, it is normally recommendable thatthickening time tests be made, in the laboratory, on the specificcomponent parts of the slurry (or paste) prior to the actual cementingjob. Variations in thickening times are not due solely to down holeconditions of temperature and pressure. They frequently, pragmaticallyspeaking, may be the result of irregularities in the basic cement.

Further quite pertinent art and direction in the area of well cementingand the like practices includes the Report Prepared By The APIMID-CONTINENT DISTRICT STUDY COMMITTEE ON CEMENTING PRACTICES ANDTESTING OF OIL-WELL CEMENTS issued by AMERICAN PETROLEUM INSTITUTE(i.e., "API"), Division of Production, in Dallas, Tx. 75201 as APIBulletin D-4, Corrected Edition of March 1963, entitled "The Effects OfDrilling-Mud Additives On Oil-Well Cements"; "API Specification ForOil-Well Cements And Cement Additives" (API Std 10A, Fourteenth Edition,dated April, 1969); and "API Recommended Practice For Testing Oil-WellCements And Cement Additives" (API RP 10B, Sixteenth Edition, datedApril, 1969).

PATICULARIZED BACKGROUND OF THE INVENTION

Various and numerous sulfonated and otherwise derived lignin materialshave already been found, known and developed and advantageously appliedin well cement compositions as retarding agents therefor. U.S. Pat. No.2,880,102 is specifically illustrative of this. Considered generically,these lignosulfonate materials even include the alkaline oxidized,partially desulfonated lignosulfonates of the type prepared according tothe teachings and disclosures of U.S. Pat. No. 2,491,832 which areprepared from treatments of alkaline sulfite waste pulping liquor fromwood conversion.

While numerous references are available dealing in one capacity ordiscipline or another with the identity and nature of lignin, per se,and many of the derivatives of lignin including lignosulfonates (all ofwhich, by the way, are generally relatively imprecise and not positivelydefinite), preparation and multitudinous uses of the contemplatedmaterials, substantial elucidation thereupon and thereof may also befound, by way of illustration, in U.S. Pat. Nos. 1,848,292; 2,371,136;2,371,137; 2,505,304; 2,576,418; 2,598,311; 2,800,449; 3,156,520; and3,726,850. Still additional art of interest is uncovered in U.S. Pat.No. Re. 18,268; U.S. Pat. Nos. 2,057,117; 2,104,701; 2,399,607; and2,434,626.

Another excellent informational source in this area is the Bulletin (No.131) published by AMERICAN CAN COMPANY of Greenwich, Connecticut 06830(U.S.A.) entitled "Chemicals From Wood".

The alkaline oxidized, hydrolyzed, partially desulfonatedlignosulfonates which are utilized as the starting materials to obtainthe retardant resulfonated lignosulfonate additives used in and for wellcementing compositions, and so forth, in practice of the presentinvention are, as indicated, usually most readily and convenientlyobtained pursuant to the teachings of U.S. Pat. No. 2,491,832. In thispatented process, especially if and when enhanced by-product yields ofvanillin are wanted, it is frequently more desirable to employ a wastepulping liquor for the process which is derived from a totally, or atleast substantially, softwood source--although this is not an entirelyrestrictive limitation since hardwood starting materials may also beused.

Using the process patented in U.S. Pat. No. 2,491,832, the degree ofdesulfonation realized is a factor of and controlled by the amount ofcaustic interjected for the reaction; the strength of the oxidationeffected (i.e., the relative amount of air or oxygen employed--beingcareful to avoid such severe oxidation conditions as might inducedemethylation); the reaction time and temperature schedules followed,and the solids dilution, generally aqueous, of thelignosulfonate-containing spent sulfite liquor effluent being treated(with greater dilution conditions tending to lead to more extensivedesulfonation probably due to the thereby increased availability of thereacting molecules to the oxidizing influence applied).

While very desirable partially desulfonated lignosulfonate materials areprepared with the alkaline oxidation conducted on a spent sulfite liquorcontaining, on a weight percent basis, from about 30 to 35% of dissolvedsolids, the spent liquors being cooked in the desulfonation process mayhave as little as 14-10% to as much as 40% solids content in order toobtain beneficial desulfonated products.

Practically, almost any caustic alkaline solution can be employed foreffecting the partial desulfonation reaction, although lower alkalinitygenerally results in less desulfonation. More caustic is required whensugars and other saccharides are present (and they are usually presentwith otherwise untreated spent sulfite liquors) in any varied or moresubstantial amounts in order to effect the decomposition of suchsaccharides. Ordinarily, very good results are achieved when sufficientcaustic concentration is maintained throughout the desulfonating cook tomaintain the reaction mass in the relatively high pH range of betweenabout 10.5 to about 11. For example, a quite satisfactory proportion oflignosulfonate solids to caustic to employ in the reaction mass involvesuse of an aqueous lignosulfonate solution of about 31-32 wt. % andhaving a specific gravity around 1.22-1.24 or so containing a causticconcentration in the solution of about 140 gms. NaOH/liter.

Adequate oxidation conditions to achieve desired ranges of desulfonationof the lignosulfonate in the spent sulfite liquor may be achieved byproviding, almost invariably from either air or oxygen passed throughthe cooking reaction mass, between about 20-25 or so and about 40-50 orso grams of elemental oxygen (i.e., O₂) per each 100 grams of lignin inthe lignosulfonate material being desulfonated. In actual practice toobtain a frequently more desirable range of partially desulfonatedmaterial, between about 27 and 35 grams of O₂ per gram of lignin areutilized.

While variations may be encountered, temperatures on the range of fromabout 140° C. to about 170° C., advantageously in the neighborhood of165° C., are usually most desirable to utilize. Of course, the reactingmass is cooked until the desired degree of desulfonation (or, whenvanillin by-product is important, the desired yield of it) is obtained.Usually and at the 165° C., level the cooking time is on the order of 45minutes or so; the optimum time to employ, as will be appreciated bythose skilled in the art, depending on reaction conditions and theparticular degree of desulfonation desired in the resulting partiallydesulfonated lignosulfonate material. It is oftentimes most advantageous(if not literally necessary for material handling purposes) to terminatethe cooking while some free caustic still remains in the reaction mass.This tends to prevent problems of emulsification during subsequentrecovery of the partially desulfonated lignosulfonate. Beneficially andfor the indicated purpose, the reaction may accordingly be finishedwhen, say, about 4-5 gms./liter of free NaOH is found to remain in thereaction mass.

Practice of the process of U.S. Pat. No. 2,491,832 yields, in effect, aspent oxidized liquor which, as has been disclosed and as is known,contains partially desulfonated, generally acid-insoluble, chemicallyaltered organic lignin substances. These are usually isolated and/orfractionated by acid (namely, sulfuric) precipitation which eliminatesvarious sludge-producing, mostly calcium-based, ingredients therein.After the precipitation, the purified partially desulfonatedlignosulfonate material is generally dissolved in caustic to yield asodium salt; then spray or otherwise dried to yield a powderproduct--although, if desired, it may be finally prepared and used in anundried liquified form or reconstituted to an aqueous liquid of anydesired concentration.

The partially desulfonated lignosulfonate material thus obtained is notdirectly procurable from original spent sulfite liquors as are thenormally-gotten and ordinarily so-called, albeit undesulfonated,"lignosulfonates" (the "water soluble" calcium or equivalentlignosulfonate salt or lignosulfonic acid described in U.S. Pat. No.2,880,102 being typical of same). To the contrary, the partiallydesulfonated lignosulfonate additive products of reference areexceptionally pure materials containing essentially no sugars orpolysaccharides and having only vanishing traces, if any, of combinedsulfur in sulfite form; and further having other inherent distinguishingfeatures including relatively uniform and substantially constantrelative molecular size characteristics.

Although a sugar and saccharide-containing spent sulfite liquor isdesirable to employ as the starting material for preparation ofpartially desulfonated lignosulfonates from which the resulfonatedcompositions used as cement retardants in the present invention arederived, otherwise treated spent sulfite liquors may equivalently beutilized. These, for example, may be those which have previously beentreated in divergent ways and for other initial conversion purposeswherein the sugars and/or saccharides are utilized and consumed, as inthe preliminary manufacture from raw spent sulfite liquor of yeast oralcohol or in other ways giving a sugar and/or saccharide -reduced or-free spent sulfite liquor.

The alkaline oxidized, partially desulfonated lignosulfonates which areanionic polyelectrolytes with molecular weights usually on the order of1,000 to 20,000 and from which the resulfonated products employed ascement retardants pursuant to instant practice are obtained generallyhave an organic sulfonic sulfur, i.e., --SO₃, content, calculated aspercent sulfur by weight of broadly between about 1/2 and about 5 wt. %.More advantageously for many purposes, this sulfur range is betweenabout 13/4 and about 31/4 wt. %; while quite often it is preferable forthe partially desulfonated lignosulfonate to contain from about 2.2 toabout 2.8 wt. % of the combined sulfur in the sulfonic form.

A commercially available product, "MARASPERSE CB" (™), obtainable fromAMERICAN CAN COMPANY, is an example of an alkaline oxidized, hydrolyzed,partially desulfonated lignosulfonate material useful as the startingmaterial from which to derive the solubilized, re-sulfonatedlignosulfonates cement retarding additives of the present invention.

"MARASPERSE CB", as usually available, generally has the followingtypical analysis parameters and physical characteristics features:

    ______________________________________                                        TYPICAL ANALYSES (Moisture-Free and Wt. % Basis):                             pH - 3% Solution         8.5-9.2                                              Total Sulfur as S, %     2.5-2.9                                              Sulfate Sulfur as S, %   0.1-0.25                                             Sulfite Sulfur as S, %   0-0.05                                               CaO, %                   0.02-0.05                                            MgO, %                   Trace-0.03                                           Na.sub.2 O, %            9.4-9.9                                              Reducing sugars, %       0                                                    OCH.sub.3, %             12.4-12.9                                            Sodium Lignosulfonate, % 99-99.6                                              Solids, %                92-94                                                ______________________________________                                        ULTRAVIOLET ANALYSES (K-value representing base line):                        Upper UV:                                                                     K solids at Max. (275 mu)                                                                              29-30.5                                              K OCH.sub.3 Max.         225-250                                              Differential UV:                                                              Max. nm                  250-252                                              K Solids at Max.         10-11.3                                              K OCH.sub.3 at Max.      82-88                                                Baseline K Solids        9.5-10.5                                             Phenolic OH, %           1.8-2.1                                              OH/OCH.sub.3             0.26-0.30                                            ______________________________________                                        PHYSICAL CHARACTERISTICS:                                                     Usual Form               Powder                                               Moisture Content (Max., % H.sub.2 O)                                                                   8.0                                                  Color                    Black                                                Bulk Density (lbs./cu. ft.)                                                                            43-47                                                Solubility in Water (%)  100                                                  Solubility in Oils and                                                        Most Organic Solvents (%)                                                                              0                                                    Surface Tension, 1% Sol'n                                                     (in dynes/cm)            ca. 51.4                                             ______________________________________                                    

While the known alkaline oxidized, hydrolyzed, partially desulfonatedlignosulfonates, including such things as "MARASPERSE CB", are excellentsurfactant, dispersant, detergent and otherwise attractively-propertiedmaterials which are very good as cement retarding additives under manycircumstances, they still have certain intrinsic inadequacies andlimitations leaving some desiderata and unfulfilled capability for usein many crucial well cementing applications and for expandedapplicability in and for this highly advantageous purpose. Noteworthyamongst these are difficulties in the employment of the mentionedpartial desulfonated lignosulfonates are their relatively limitedsolubility in saline solutions plus their sometimes not totallysatisfactory reliability and predictability as to set retarding and gelcontrol, especially time-wise, of well cement compositions and pastes inwhich they are incorporated.

FIELD AND OBJECTIVES OF THE INVENTION

This invention pertains to and resides in the general field of wellcementing in the area of new and improved cementing and the likecompositions and their method of preparation; more particularly as to agreatly effective highly saline salt solution tolerant and predictablegel control and retardant additive agent for exceptionally beneficialand useful well cementing operations. The agent involved in the wellcementing compositions and preparation thereof in practice of thepresent invention is an exceptionally pure lignosulfonate derivative ofthe type disclosed in the copending, concurrently filed Application forUnited States Letters Patent of the present Applicants entitled"SOLUBILIZED LIGNOSULFONATES DERIVATIVIES" having Ser. No. 671,397,filed Mar. 29, 1976 (U.S. Pat. No. 4,069,217). Provision of the vastlyimproved well cementing compositions and techniques (includingpreparation thereof) in and for many of a very wide gambit of wellcementing and the like purposes as well as many other of the salientpropensities and capabilities and satisfactory characteristics ofpresently-contemplated practice is amongst the principal aims andobjectives of the invention.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a graph showing the relative molecular size properties of thelignosulfonate additives of the invention in contrast to conventionalproducts known heretofore.

FIG. 2 is a graph illustrating the setting time predictabilitycharacteristics of the lignosulfonate additives of the invention incomparison with standard well cementing lignosulfonates knownheretofore.

PARTICULARIZED DESCRIPTION OF THE INVENTION

Conventional oil well cements and the like comprised of hydrauliccement, sometimes and optionally colloidal clay or equivalent, andvarious additaments in small proportions are known. They are generallysupplied as premixes to be slurried at the well site with water forintended usage in the well.

The well cementing compositions of this invention are, basically, ahydraulic cement preparation (which, as may be desired, can also becomprised of clays and the like and/or other functional additaments)containing as a gel control and retardation additive agent aresulfonated derivative of the above-described and identified alkalineoxidized, hydrolyzed, partially desulfonated lignosulfonates. Besidestheir unique chemical constitution, the additive agents employed arecharacterized in having (as compared to most other so-calledlignosulfonates) an evened-out and/or very similarly dimensionedrelative molecular size range within a 10-20% size measure from anygiven constant (particularly in volumetric comparison with the molecularsize of 2-naphthalene sulfonic acid); a solubility--especially asregards saline solution tolerance or compatibility and/or in aqueousacidic media at least 10 percent and usually 2 or 3 times greater thanthat of the partially desulfonated lignosulfonate starting material fromwhich the resulfonated additives used in the present invention arederived; and a substantially increased, i.e., at least 50 percent and upto 15-20 times surfactant and dispersant activity.

The resulfonated additive materials for the well cements are readilyobtained by the direct sulfonation or sulfoalkylation of the referencedalkaline oxidized, hydrolyzed, partially desulfonated lignosulfonatestarting material. Ordinarily and most conveniently, this is done withappropriate sulfonating reagents in an aqueous solution of the startingmaterial, advantageously using agitation during the reaction (which isbetter when applied vigorously and may be either by mechanical mixing orstirring and/or from the agitating effects of steam being pressed intothe reaction mass when steam is used for heating), at any desiredsuitable temperature. In general, the reaction can be conducted over atemperature range from about 50° C. to about 200° C., although it isordinarily desirable to run at least at the boil (i.e., about 100° C. orso) in order to avoid unduly long reaction times. Ordinarily, atemperature on the order of 160° C. is satisfactory for most of theresulfonations done. Of course, the reaction is accomplished undercorresponding pressure when temperatures over boiling are utilized. Thetime of reaction generally varies with the temperature involved; lowertemperatures requiring longer times. At higher temperatures theresulfonations can be completed in as little as 1/2 hour or so whiletemperatures at the lower end of the scale may require as much as 16 ormore hours for completion. When conducted at about 160° C., theresulfonation cooking is usually completed within about an hour.

Any suitable sulfonation reagents may be used for the resulfonationreaction. When straight sulfonations are desired, they may beadvantageously accomplished with an alkali metal (such as sodium)bisulfite or sulfur dioxide. Sulfoalkylations, as are frequently quitedesirable, are done with mixtures of an appropriate lower alkyl aldehydeand a bisulfite. The sulfonate group, per se, that is attached instraight sulfonation is, of course, --SO₃ H. The sulfoalkylates, whichordinarily involve 1 to 3 carbon atom alkyl units, are of the structure--(CH₂)_(x) --SO₃ H, wherein x is usually an integer from 1-3 and when xis plural the alkyl unit may be linear in attachment or, as is probablythe more frequent case, comprised of side-chain arrangements.

The aldehyde utilized in at least approximative stoichiometricproportions with the bisulfite in the sulfoalkylations preformed for theresulfonation is generally of the structure: RCH:O, wherein R is anydesired 0-3 carbon atom-containing alkyl group. Obviously, if desired,mixed aldehyde reaction systems may be utilized even though there isordinarily no particular advantage in this. Usually, it is verydesirable to accomplish the resulfonation with a sulfomethylatingreaction using formaldehyde (CH₂ O) and sodium bisulfite (NaHSO₃) asreagents so as to make sulfomethyl (--CH₂ SO₃ H) attachments in theresulfonated product.

As indicated, about stoichiometric relative proportions of the aldehydeand bisulfite reagents are employed for the resulfonation; these beingused in amounts calculated to effect the desired extent or quantity ofsulfonic acid units in the finally obtained resulfonated product.Actually, a plus or minus 20% tolerance from exactly stoichiometricratios is tolerable. In sulfomethylating reactions, the amount offormaldehyde used may vary from about 11/2 to about 12 wt. % of thedesulfonated starting material being resulfonated while the bisulfitecan correspondingly be utilized in quantities, on the same basis, ofbetween about 5 and about 40 wt.%. A particularly desirableresulfomethylated product containing about 51/2 wt. % of sulfur inorganic sulfonic sulfonate form is obtained by the reaction in thedescribed manner of "MARASPERSE CB" with about 15 wt. % of sodiumbisulfite and 41/2 weight % of formaldehyde, based on "MARASPERSE CB"weight, cooked for one hour at 160° C.

The resulfonated products used as additives for well cementingcompositions in practice of the present invention may, as desired,contain anywhere from about 11/2 wt. % to 14-15 wt. % of total sulfur incombined organic sulfonic sulfonate form. Advantageously the range ofsuch sulfur is between about 23/4 and about 10 wt. %, with greaterdesirability oftentimes attained in the sulfur wt. % range of from about41/2 to about 61/2 wt. %.

While it is not intended to bound by any particular theory, it isbelieved that the starting alkaline oxidized, hydrolyzed partiallydesulfonated lignosulfonate material (as obtained when following theprocedures of U.S. Pat. No. 2,491,832) has the sulfonic acid groupattachments at least substantially if not predominantly or entirely onthe side chains of and in the lignin molecules, this ordinarily being onthe side chain carbons which are in the alpha position relative to thering and carrying over from the initial substitutions made during theoriginal sulfite pulping operations. On the other hand and surprising asit is, it is believed the sulfonate and/or sulfoalkyl units prepared inpractice of the present invention are substantially if not predominantlyor entirely positioned in ortho and/or para substitutions on thearomatic rings of the lignin molecules. Thus, the resulfonated productused in practice of the instant invention as a well cement additive is,quite obviously, a basically different and dissimilar lignosulfonatefrom and as compared to the lignosulfonate material found in spentsulfite liquors from which are obtained the starting lignosulfonatesthat are resulfonated in present practice.

A typical resulfonation reaction for manufacture of the additivespursuant to the present invention may be figuratively represented by thefollowing, presumed-to-be-accurate chemical reaction formulae: ##STR1##

The resulfonated, alkaline oxidized, hydrolyzed partially desulfonatedwell cement (or cementing paste) additives of the present invention aregenerally employed in amounts, based on total resulting compositionweight, between about 0.05 and about 3 wt. %. More often, the additiveconcentration employed is from about 0.2 to about 1.5 wt. % whilefrequently the most desirable range is from, say, 0.3 to 1 wt. %.

The particular quantity of additive employed generally depends in verylarge measure on the cement setting schedule (according to API criteria)being followed and the temperature encountered during actual setting ofthe cement composition. Usually, relatively more of the retarderadditive is required when higher setting temperature conditions areencountered.

The additive resulfonated desulfonated lignosulfonates utilized inpractice in accordance with the present invention are characterized inimparting to the cement compositions in which they are incorporated anexcellent tolerance and resistance against premature settings andgellations under exposure to severely strong saline environments such asare frequently found in many wells due to the presence therein byinfiltration or seepage of natural salt (including sea) waters. Theyalso tend to ensure an uncommon and unusual accurate predictability asto cement setting character, speaking time-wise, in the compositionsunder any given setting temperature and schedule; this being ofobviously considerable advantage and importance for the most effectiveand beneficial application and efficient utilization of a well cementingcomposition or paste.

The compositions of the present invention are, and very desirably so,essentially gellation-free admixtures. In this, they avoid the frequentproblem of gellation experienced with many cement retarder additivesthat are known and have been used in well cementing operations. As isreadily appreciated by those skilled in the art, this is a veryimportant factor especially for purposes of laboratory and other thanactual usage test and evaluation procedures. Very beneficially in thisregard, the compositions of the present invention invariably do notexhibit or cause with premature gellation any consequent and so-calledpseudo false settings.

EXEMPLIFICATION OF THE INVENTION

The following detailed Illustrations more particularly delineate andshow the extraordinary benefits and advantages obtained in and bypractice of the present invention and with the exceptionally useful andversatile resulfonated lignosulfonate composition products involved forwell cement additive utilizations.

FIRST ILLUSTRATION

Excellent quality resulfonated additives, containing about 5.5 wt. % oforganic sulfonic sulfur (based on composition weight) are made in largescale preparations by the sulfomethylation of "MARASPERSE CB" containingabout 2.6 wt. % of total sulfur measured as S according to the followinggeneral procedure (in which all percentages are on a weight basis):

(A). Synopsis of Procedure:

The "MARASPERSE CB" liquor is sulfomethylated by cooking one hour at160° C. with 15% NaHSO₃ and 4.5% CH₂ O.

    ______________________________________                                        Molecular Weights Of Particular Reagents Involved:                            ______________________________________                                        Formaldehyde      CH.sub.2 O 30                                               Sodium Bisulfite  NaHSO.sub.3                                                                              104                                              ______________________________________                                    

(B). Bill of Materials:

    ______________________________________                                                Basis:  Basis: Approximate                                                    Per 100 lbs.                                                                           6000-gallon Batch                                                    Finished                                                                              Gallons          Solids,                                              Product In                                                                            (U.S.    Pounds  lbs./ Pounds                                         lbs. Solids                                                                           Measure) Liquid  gal.  Solids                                 ______________________________________                                        "MARA-                                                                        SPERSE CB"                                                                    Liquor    85.50     5,400    52,800                                                                              3.71  20,000                               Formaldehyde                                                                            3.85      270      2,450 3.33  900                                  Sodium                                                                        Bisulfite 12.80              3,000       3,000                                Total     102.15             58,250      23,900                               Finished                                                                      Additive                                                                      Product   100                            23,400                               ______________________________________                                    

(C). Procedure in Detail:

I. Pump "MARASPERSE CB" liquor to process tank (about 5500 gallons);

2. Measure the volume in the tank;

3. Take a pint sample;

4. Check temperature and specific gravity of the liquor;

5. Determine the pounds per gallon of liquor solids from the gravityreading;

6. Agitate and steam the liquor to about 80° C. then

7. Add 4.5% formaldehyde based on the "MARASPERSE CB" liquor solids (A490-lb. drum of formaldehyde at 37% solids containing 180 lbs.formaldehyde);

8. Slowly and with good agitation, add 15% sodium bisulfite based on"MARASPERSE CB" liquor solids (taking into account that if this is addedtoo fast, it will not mix in); then

9. After the bisulfite is completely mixed in, continue agitation for 15minutes.

II. Reaction--

1. Transfer about 1850 gallons of liquor to a feed tank for the hightemperature, pressure reaction vessel while maintaining the temperatureat about 80° C.

2. Dump the liquor from the feed tank to a stirred, autoclave-type,pressure, reactor;

3. Steam to 160° C.;

4. Cook one hour at 160° C.;

5. Blow the cook slowly to avoid foaming;

(D). Process Variables:

The "MARASPERSE CB" liquor should have a gravity of 1.16 to 1.18 at roomtemperature, (3.5 to 3.9 lbs. solids/gallon) with maximum soluble limeless than about 0.1% CaO. The addition of the bisulfite to the liquor iscritical. This must be done very slowly to avoid forming a crust on thesurface, which is very difficult to break up.

Following the preparation, the products are readily obtained in solid(usually powdered) alkali metal (i.e., generally sodium) salt form byspray or other drying procedures.

The resulfonated lignosulfonate products obtained from theabove-specified preparation procedure have outstanding qualities andcharacteristics as well cement retarders in all of the particularsspecified in the foregoing "PARTICULARIZED DESCRIPTION OF THEINVENTION". The additives are: soluble in synthetic and natural (such asNorth Sea water) salt solutions; dissolvable with ease in acid media aslow as pH 1.5 or so; markedly surfactant; and have a very closemolecular size range constancy of easily less than a 20% measure (andusually closer to 10% and frequently much less in this) when collated toa given standard size of molecule such as 2-naphthalene sulfonic acid(i.e., "2-NSA") as indicatable by diffusion tests through micro-sizeporous filter media consisted of cellulose type cell membranes, orfilters, having average pore sizes of 0.4 microns.

The graph presented in FIG. 1 of the accompanying Drawing nicelydemonstrates as a typical representation the very close relativemolecular size constancy of the resulfonated lignosulfonate retarderadditives utilized in practice of the present invention as compared toconventional and heretofore-known "lignosulfonate" products. As isapparent therein, the resulfonated desulfonated lignosulfonate additivesfor use in the present invention have (in contradistinction with normaland ordinarily obtained "lignosulfonates") the described relativelynarrow relative molecular size average particulars.

The resulfonated products obtained by the foregoing Procedure are allfound to be extremely useful and effective retarding agents to preciselycontrol and regulate the setting under high temperature and pressureconditions even in highly saline aqueous environments.

Similar very good results, using appropriate reagents for the purpose,are realized when the resulfonated products and made by directnon-alkyl-group-containing sulfonations as well as for sulfoethylations,sulfopropylations and so forth.

SECOND ILLUSTRATION

Using resulfomethylated products prepared according to the FirstIllustration, a number of salt tolerance tests in extremely highconcentration synthetic aqueous saline solution are performed. In each,the salt solution is made up in water to a total volume of 1 liter andis composed, in the water, of 50 gms. of sodium chloride (NaCl), 16.5gms. of calcium chloride (CaCl₂) and 15.5 gms. of magnesium chloride(MgCl₂). About 0.50 gms. of the lignofulfonate additive material beingtested is put into 2 fluid ounces (about 60 ml) of the solution. Another50 ml. of the salt solution is then added to the mixture and the entiremake-up manually shaken briefly to effect whatever preliminarydissolution can be achieved; after which it is put on a mechanicalshaker for one hour to ensure as much solubilization as possible.Subsequent to that, a 10 ml. portion of the overall mixture is placedinto a graduated container tube from a standard laboratory-type DeLavalCentrifuge and centrifuged for 5 minutes thereon at 20,000 RPM. Thevolume percent of sludge found after the centrifugation (based onoriginal volume of centrifuged material) is then measured. In all cases,the resulfonated products of the First Illustration have never more than2.0 and usually (at least about 9 out of 10 times) less than 1.6 volumepercent of removed sludge after the centrifugation. In contrast and byapplication of the same saline solubility test, the general type of"MARASPERSE CB" starting material utilized in the First Illustration hasabout a 6 volume percent sludge level after the centrifugation analyses.

Analogous results are obtained when the same saline solubility tests arerepeated excepting to utilize, as the aqueous saline media; (i) 200grams/liter. NaCl solution; and/or "North Sea" water comprised, perliter, of 30.0 gms. NaCl, 1.16 gms. CaCl₂ and 5.54 gms MgCl₂ (giving atotal dissolved content of 36.70 gms./liter of such salts).

THIRD ILLUSTRATION

A desulfonated lignosulfonate from the vanillin process containing 0.7wt. % combined sulfur as organic sulfonic sulfonate was attempted, in a5 gm. quantity, to be dissolved in 50 ml. of pH 1.5 sulfuric acid thenfiltered through a fine mesh filter. The attempted solution was veryturbid in appearance and, after passage through the filter (during whichit filtered very slowly), left 4.7 gms. of undissolved solids out on thefilter paper.

In contrast, three resulfonated or resulfomethylated products made fromthe same desulfonated starting material were subjected to the same test.Sample "X" of the resulfonated or resulfomethylated product contained1.5 wt. % combined sulfur, Sample "Y" 2.3% and Sample "Z" 2.0%. TheSample "X" solution was slightly turbid and filtered slowly but leftonly 0.2 gms. of undissolved solids on the filter paper. Sample "Y" wasa clear brown liquid in the strong acid solution but filtered quiterapidly and left no residue (i.e., actually 0.0 gms.) on the filterpaper which remained clean after filtration. Sample "Z" while producinga slightly turbid solution, also filtered rapidly and left no measurableresidue on the filter paper which appeared only very slightly discoloredafter the filtration.

FOURTH ILLUSTRATION

A sample of "MARASPERSE CB" (2.6 wt. % S) and, for comparative purpose,a sample of a resulfomethylated derivative thereof made to a 51/2 wt. %S content according to the procedure of the First Illustration weretested as dispersants for Stellar clay according to the well-known,standard ASP-200 Stellar Clay Test using for the measurement a FannRotational Viscosimeter obtained from the Fann Instrument Company ofHouston, Tex. Values for yield point, zero gel and Fann 600°, 300°,200°, 6° and 3° settings were obtained. The data obtained, of course,represents the force required to move a stationary clay system throughthe plug flow to plastic flow condition in a pipe with the numericalmeasurements taken in lbs./100 ft.² of pipe surface; lower readingsindicating better dispersant effect by the additive as the consequenceof requiring less force for the movement of the mixture through theapparatus. The results were as follows:

    __________________________________________________________________________                      Fann°                                                              Yield                     Zero                                  Product       Point                                                                             600 300 200 100 6  3  gel                                   __________________________________________________________________________    "MARASPERSE CB"                                                                             69  91  80  72  63  39 34 36                                    RESULFOMETHYLATED                                                             DERIVATIVE    16  34  25  22  18  13 13 15                                    __________________________________________________________________________

The superiority of the additive made for retarder use in accordance withthe present invention is easily discernible and plainly evident from theforegoing.

FIFTH ILLUSTRATION

A series which included a composition of a normal (and not resulfonated)desulfonated lignosulfonate (as obtained from spent oxidized liquor fromthe vanallin process generally pursuant to the above-identified U.S.Pat. No. 2,491,832) and resulfonated (more precisely, resulfomethylated)derivatives thereof prepared according to the First Illustration hereofwere tested for their propensities and capabilities to disperse andcontrol the setting retardation times of Type I cement (i.e., similar tothat prescribed in ASTM C150 Specifications) using The Fann ViscosimeterApparatus (as described in the above Fourth Illustration) to finallymeasure the results. Each of the test sample compositions was made upwith 300 gms. of the Type I cement (obtained from IDEAL CEMENT COMPANY),25 gms. of NaCl (giving, in effect, in the final composition about a 15wt. %, based on total composition weight, aqueous salt solution), 3 gms.of the lignosulfonate additive and 138 ml. of distilled water. In eachcase, the composition to be tested was preliminarily prepared by adding,in a laboratory-style Waring Blender operated at low speed: thelignosulfonate dispersant to the water; then the salt; followed by thecement. Shearing of each constitution was done for 10 minutes at a 40volt setting (60 cycle AC) of the Blender. After the mixing, each samplemix was placed in the appropriate testing cup to each of which was addedone drop (i.e., about 0.1 cc.) of octanol before placing each fortesting in the Fann Viscosimeter. The results were as set forth in thefollowing tabulation, wherein Sample "D" was the starting desulfonatedlignosulfonate (obtained, as above-described, from a vanillin process)containing 0.66 wt. % of organically combined sulfonic sulfonate sulfur;while Samples "A", "B" and "C" were resulfomethylated derivativesthereof containing, respectively, 2.10-2.29-3.65 wt. %'s of sulfonicsulfur with additional minor quantities of non-sulfonic sulfur containedtherein (all as determined by the method described at pg. 850 of"Analytical Chemistry" in Vol. 32, No. 7, for June 1960).

    __________________________________________________________________________            Fann°                                                          Sample                                                                            Yield                     Zero                                                                             Setting Time                                 No. Point                                                                             600 300 200 100 6  3  gel                                                                              To Light Gel                                 __________________________________________________________________________    "A" 102 164 133 120 104 59 48 53 3 hrs.                                       "B" 101 159 130 116 101 56 43 53 3 hrs.                                       "C"  70 114 92  87  70  49 32 37 4 hrs.                                       "D" 112 176 144 128 111 60 50 62 2 hrs.                                       __________________________________________________________________________

These data very well illustrate the improvement in cement retardationachieved with the retarder additives employed in practice of the presentinvention.

SIXTH ILLUSTRATION

A resulfonated desulfonated lignosulfonate retarder additive having thechemical composition specified in the Fourth Illustration was added tofive different, popular, known and commercially widely employed cementsfor well paste preparations and each tested for setting time per APISchedule 8 using the conventional Pan American Test Apparatus Procedure.

Analogous compositions were prepared excepting to use as the retardingagent additive a well known product often employed for the purpose whichwas a partially purified, sugar-destroyed, calcium-based lignosulfonateobtained from AMERICAN CAN COMPANY and identified commercially as"MARABOND 21" (TM).

The comparative results obtained are set forth in the graph of FIG. 2 ofthe accompanying Drawing which clearly and convincingly evidences thesuperior setting time predictability realized in use of the resulfonateddesulfonated retarder additives of the present invention. Thesecompositions, additionally, gave no gellation problems.

SEVENTH ILLUSTRATION

Good results are obtained when the Samples "X", "Y" and "Z" resulfonateddesulfonated lignosulfonate materials described in the ThirdIllustration are employed as retarding agents in amounts varying from0.2 to 1.2 wt. % of the composition and tested in "LONE STAR No. L"(Class H), "LONE STAR MT" (Class H) and "IDEAL DSU" (Class G) cementsusing Well Simulation Tests (per API RP-10B) over Schedules 4, 5, 6, 7,7B and 8. Thickening times (without problems of gellation) of from about11/2 to 41/2 hours are experienced with the various retarded cementcompositions prepared and tested.

EIGHTH ILLUSTRATION

The resulfonated desulfonated lignosulfonate additive identified in theFourth Illustration was tested at various concentration levels in ClassH cement to check setting times obtained with both fresh water and saltwater exposures. The excellent results obtained were as set forth in thefollowing tabulation (with, again, no gellation experienced):

    ______________________________________                                        12,000 ft. Casing Schedule - 172° F.                                   Wt. % Retarder                                                                           Fresh Water Time                                                                             18% Salt Water Time                                 0.2        1 hr., 47 min. 2 hrs., 43 min.                                     0.3        3 hrs., 30 min.                                                                              3 hrs., 32 min.                                     0.4        4 hrs., 5 min. 5 hrs., 14 min.                                     0.5        6 hrs., 14 min.                                                                              6 hrs., 30+ min.                                    ______________________________________                                        14,000 ft. Casing Schedule - 206° F.                                   Wt. % Retarder                                                                           Fresh Water Time                                                                             18% Salt Water Time                                 0.3        1 hr., 58 min. 1 hr., 44 min.                                      0.4        3 hrs., 1 min. 2 hrs., 27 min.                                     0.5        3 hrs., 47 min.                                                                              2 hrs., 45 min.                                     0.6        4 hrs., 9 min. 3 hrs., 42 min.                                     0.7        5 hrs., 12 min.                                                                              4 hrs., 33 min.                                     0.8                       5 hrs., 12 min.                                     ______________________________________                                    

Equivalent good results are likewise obtainable with other of theabove-delineated resulfonated desulfonated lignosulfonate additiveproducts pursuant to the practice of the present invention includingstraight (i.e., non-alkyl-unit-containing) organically sulfonated andresulfonated materials and various sulfoethylated and sulfopropylatedresulfonated desulfonated lignosulfonate derivative additives.

Many changes and modifications can readily be made and adapted inembodiments in accordance with the present invention withoutsubstantially departing from its apparent and intended spirit and scope,all in pursuance and accordance with same as it is set forth and definedin the hereto appended Claims.

What is claimed is:
 1. In the process of drilling wells and borings intothe earth's surface, including the injection of a hydraulic cementmixture thereinto, the improvement that comprises including in saidhydraulic cement mixture, between about 0.05 percent and about 3 percentby weight of the resulting mixture, of a retarding agent composition forsaid hydraulic cement mixture that isan alkaline oxidized, hydrolyzed,partially desulfonated and subsequently resulfonated lignosulfonate,said resulfonated lignosulfonate having substituted therein as theresulfonation units, those of the formula:

    --SO.sub.3 H,

said resulfonated lignosulfonate containing, on a percent by weightbasis, based on composition weight, between about 11/2 weight percentand about 15 weight percent of total sulfur in combined organic sulfonicsulfonate form; said lignosulfonate prior to resulfonation having arelative molecular size of substantially 1,000 to 20,000.
 2. A processas claimed in claim 1, wherein said retarding agent composition includesbetween about 23/4 and about 10 weight percent of said total combinedsulfur.
 3. A process as claimed in claim 1, wherein said retarding agentcomposition includes about 41/2 weight percent and about 61/2 weightpercent of total combined sulfur.
 4. A process as claimed in claim 1,wherein said retarding agent composition is present in the form of analkali metal salt.
 5. A process as claimed in claim 4, wherein said saltis a sodium salt.
 6. A process as claimed in claim 1, wherein saidcomposition is further characterized by a relatively constant relativemolecular size range with a molecular size variation within said rangeof not more than about 20 percent.
 7. A process as claimed in claim 6,wherein said relative molecular size range variation is not more than 10percent.
 8. A process as claimed in claim 1, wherein said retardingagent composition is further characterized in having the introducedsulfonate units substituted at least substantially, in the resulfonated,alkaline oxidized, hydrolyzed, partially desulfonated lignosulfonatematerial, in one or more of the ortho or para positions on the aromaticrings of the lignin molecules present therein.
 9. A process as claimedin claim 8, wherein said substituted introduced sulfonate units arelocated predominantly in the ortho or para, or both, positions of saidaromatic lignin molecule rings.
 10. A process as claimed in claim 1,wherein said combined organic sulfonic sulfur is present upon completionof resulfonation in an amount by weight of from 2.75 percent to about 10percent.
 11. A process as claimed in claim 9, wherein said combinedorganic sulfonic sulfur is present upon completion of resulfonation inan amount of from about 4.5 percent to about 6.5 percent.
 12. A processas claimed in claim 1, wherein said resulfonation is undertaken in anaqueous medium and in the presence of a reactant composition comprisingabout 5 percent to 40 percent, by weight of said desulfonatedlignosulfonate, of alkali metal sulfite.
 13. A process as claimed inclaim 12, wherein said sulfite is an alkali metal bisulfite.
 14. Aprocess as claimed in claim 13 wherein said sulfite is sodium bisulfite.15. A process as claimed in claim 1, wherein said lignosulfonate afterresulfonation is characterized in being substantially completely solublein each of aqueous saline solutions and acid media having a pH of atleast about 1.5.
 16. A process as claimed in claim 1, wherein saidlignosulfonate prior to resulfonation is characterized by a pH inaqueous solution of 8.5 percent to 9.2 percent; a total sulfur contentof 2.5 percent to 2.9 percent by weight; the absence of reducing sugars;and a lignosulfonate content of at least 99 percent by weight.
 17. Aprocess as claimed in claim 16, wherein said resulfonated lignosulfonatehas a relative molecular size of
 4200. 18. A process as claimed in claim16, wherein said resulfonated lignosulfonate has a relative molecularsize of about 3500.